The contribution of historical information to flood risk management in the Tagus estuary

Estuarine areas are often affected by flood episodes with significant infrastructural and human damages caused by the overlap of different triggering factors. Currently flood risk management practices are subject to increased scrutiny by the public and relevant stakeholders requiring rigorous justification by flood risk managers and careful validation of the technical options and human and financial resources allocated to the management practice. Therefore, flood risk diagnosis through historical sources might constitute an important and effective first approach to public policies validation. In this paper is presented an estuarine flood damage database based on historical information and discussed as to the extent these types of sources can contribute to improve estuarine flood risk management in the Tagus estuary (Portugal). The paper discusses the methodological findings and limitations and highlights the usefulness of historical information integrating the results into the International Risk Governance Council (IRGC) risk management framework.